Circular rib knitting machine



Dec. 25, 1956 Filed Feb. 13, 1953 A. SHORTLAND CIRCULAR RIB KNITTINGMACHINE 3 Sheets-Sheet l IIVVE/VTOR mum-mu 3 Sheets-Sheet 2 Filed Feb.13, 1953 1956 A. SHORTLAND 75,

CIRCULAR RIB KNITTING MACHINE Filed Feb. 13, 1953 3 Sheets-Sheet 3a/lzhw /mtzml United States Patent CIRCULAR RIB KNITTING MACHINE ArthurShortland, Leicester, England, assignor to Mellor Bromley & Co. Limited,Leicester, England, a British company Application February 13, 1953,Serial No. 336,812

Claims priority, application Great Britain February 18, 1952 2 Claims.(Cl. 66-27) This invention relates to circular knitting machinesequipped with independent latch needles.

Although, broadly speaking, the invention may be applied to singlecylinder plain knitting machines, it is principally the intention toapply it to circular rib knitting machines, that is to say circularknitting machines of the kind including at least two tricked needle bedsequipped with sets of independent latch needles and having combinedtherewith cam systems for the conjoint control and operation of the setsof needles, or of associated needleactuating jacks or sliders. In thisconnection the invention is applicable to machines of the cylinder anddial type as well as of the double axially opposed, e. g. superimposed,needle cylinder type.

In a circular rib knitting machine, the needles in one bed draw loops orstitches in one direction, whilst the needles in'the other bed drawloops or stitches in the opposite direction, thereby enabling themachine to be used in the production of rib fabric and fabric withvarious purl stitch effects.

Now, in a circular knitting machine the stitch cam or cams incorporatedin the single cam system or in one of the cam systems, as the case maybe, is or are usually made adjustable for the purpose of regulation ofthe length of loops or stitches, for example to produce knitted fabricof a required quality, or/and as may be required according to the countof the yarn to be used. Heretofore, the or each stitch cam in a cylindercam box has been adjustable vertically, whereas dial stitch cams areconventionally pivoted and adjustable in arcuate paths. Thus, whenever aconventionally adjustable stitch cam was adjusted not only was theknocking-over point changed in position as required, but also theinclined leading, i. e. operative, edge of the cam was simultaneouslyshifted laterally to one side or the other. Consequently, any adjustmentof such a cam varied the precise point in the needle circle at which thelatches of the needles eifected thereby were turned over and closed bypreviously formed loops on the needles.

Accordingly, if the latches of needles in the needle bed, or eitherneedle bed, as the case may he, were turned over and closed too earlythey tended to collide with the latch guard through an opening in whicha yarn is fed to the needles at the feed. If, on theother hand, the saidlatches were turned over too late, a compensating adjustment of thelatch guard became necessary.

Moreover, when knitting on needles in both beds of a circular ribknitting machine, an adjustment of a stitch cam at a feeder frequentlyupsets the relationship between the respective turn-over points for thelatches of the needles in the two needle beds. As is well known to thoseacquainted with the art concerned this relationship is critical, and if,as sometimes happened, a stitch cam adjustment resulted in the latchesof the needles in one bed being closed at the same or practically thesame time as the latches of the co-operating needles in the other bed,the previously formed loops on the needles were naturally subjected toundue strain.

The primary object of the present invention is to provide, in the camsystem associated with a needle bed in a circular knitting machine ofthe independent latch needle type, a stitch cam or cams which is or areof improved form and adjustable in such a way as to obviate theforegoing disadvantages.

According to this invention, the or each stitch cam incorporated in thecam system combined with the needle bed, or one of the needle beds ofthe machine, as the case may be, is adjustable obliquely along arectilinear path disposed at the same angle as the operative edge of thesaid cam. By the operative edge is meant the leading edge of a stitchcam which edge, by action on the operating butts of the relevantneedles, or their associated jacks or sliders, effects retraction ofthese needles to the knocking-over point at the feeder, or theappropriate feeder, as the case may be.

By virtue of the invention, the operative edge of the or each stitch camconcerned is maintained in the same oblique line whenever the cam isadjusted in either direction; in other words, an adjustment of the saidcam does not, as previously, result in any lateral displacement of theoperative edge. For this reason, no degree of adjustment of the improvedstitch cam in either direction will vary the precise point in the needlecircle at which the needle operating butts (on the relevant needles,jacks or sliders) first come into contact with the operative edge of thecam. It follows that the turn-over point for the latches of theseneedles will remain the same notwithstanding an adjustment of the cam.

In a convenient embodiment of the invention, the opposite side edges(including the operative edge) of the or each stitch cam are parallel toeach other, and the cam is slidably mounted, for adjustment, in anobliquely disposed recess provided between appropriately inclined andcircumferentially (i. e. laterally) spaced parallel ends of two cams orcam portions secured to the cylindrical cam box, or the dial cam plate,as the case may be.

Thus, although it is principally the intention to apply the invention tothe stitch cam or cams incorporated in the cylinder cam box of a machineof the cylinder and dial type, it is also possible, as will beappreciated, to apply it to the dial stitch cams of such a machine. Asfar as a circular rib knitting machine of the superimposed needlecylinder type is concerned, stitch cams adjustable in accordance withthe invention would preferably be incor-- porated in the bottom or plainneedle cylinder. In any event, it is only necessary to apply theinvention to the cam system associated with one of the needle beds of acircular rib knitting machine.

A stitch cam which is adjustable in the manner hereinbefore describedmay conveniently be combined with a guard cam which is adjustableconjointly and simultaneously therewith along the same oblique line.

In accordance with a further feature of the invention, a stitch camwhich is adjustable in the manner hereinbefore described, may, ifdesired, be made double-ended and reversible suchwise as to enable it,depending on its position, to present to operating butts a selected oneof two knocking-over points separated, circumferentially, by a distanceequivalent to a plurality of needles.

In order that theinvention may be more clearly understood and readilycarried into practical effect, a specific example thereof applied to astitch cam incorporated in a cylinder cam box will now be described withreference to the accompanying drawings, wherein,

Figure 1 is a fragmentary portion of a cylinder cam system as seen frominside the cam box and shows, for purposes of comparison with theinvention, a vertically adjustable stitch cam,

Figure 2 is a view similar to Figure 1 illustrating a cylinder stitchcam which is obliquely adjustable in accordance with the invention;

Figure 3 is an elevational view, as seen from the outside of thecylinder cam box, of means for automatically adjusting the stitch camdepicted in Figure 2,

Figure 4 is a plan view of the same,

Figure illustrates a cylinder cam box section incorporating obliquelyadjustable stitch cams which are double-ended and reversible for theaforementioned purpose, and

Figure 6 is a similar view but with the said doubleended cams reversed.

Like parts are designated by similar reference characters throughout thedrawings.

In Figure 1, the stitch cam 1 is of conventional form and is adjustablevertically as, for example, from the lower full-line position to theupper dotted-line position, and vice versa. Whenever the cam is adjustedin this way not only is the knocking-over point changed, e. g. to varythe length of loops or stitches, but also the inclined leading edge 2 ofthe cam is shifted laterally. Thus, for instance, when the stitch cam 1is depressed vertically from the said upper to the lower position, theknocking-over point will move down from a to b, and the leading edge 2wil be shifted laterally to the left from c to d. As a consequence thelatches 3 of the needles 4 turn over and are closed earlier with risk ofcollision with the latch guard 5 through an opening 5:; in which yarn isfed to the needles. When, on the other hand, the cam 1 is raisedvertically from the lower to the upper position shown, not only will theknocking-over point move up from b to a, but the inclined leading edge 2will shift laterally from d to c with the result that the needle latches3 will be turned over and closed later; inthese circumstances the latchguard will require to be adjusted to the chain-line position. In Figure1, the needle waves, that is to say the paths followed by the heads ofthe needles 4, when the stitch cam 1 is in its full-line and dotted-linepositions are indicated at W and W respectively. One of the needles 4 isshown, in side elevation, at the left-hand side of Figure l, and in thisfigure two further needles are shown edgewise with their operating butts4a in engagement with cams of the system. Of the two last mentionedneedles, the right-hand one is approximately at the location where itslatch 3 is turned over and closed. In this regard the lateral spacing ofthe downwardly inclined, i. e. descending, portions of the two waves Wand W serves to emphasise the earlier and later closing of needlelatches resulting from a vertical adjustment of the stitch cam 1. Thevertical chain lines represent the pitch of the needles.

Referring now to Figure 2, which is laid out similarly to Figure 1 tofacilitate comparison, it will be seen that the improved stitch earn 6incorporated in a section of a cylinder cam box, indicated at CB in eachof Figures 3 and 4, has a mainly straight operative edge 7 which isinclined at an angle of 48 or thereabouts with respect to the horizontalupper and lower edges of the cam box. The opposite edge 8 of. the stitchcam 6 is straight from end to end and extends parallel to its operativeedge 7. The cam' 6 is slidably mounted in an obliquely disposed recessformed between inclined and circumferentially spaced parallel ends 911and a of two cams 9 and 10 fixed to the inner wall of the cam box CB.The lower edge of the fixed cam 9 immediately adjacent to the inclinedoperative edge 7 of the slidable stitch cam 6 is mainly straight andhorizontal but is somewhat downwardly curved at 9b where it adjoins thesaid operative edge suchwise as to provide a stitch drawing surface. Itis in the region defined by the rounded corner between the underside ofthis fixed cam 9 and the operative edge 7 of the slidable stitch cam 6that the latches 3 of the cylinder needles 4 are turned over and closedas these needles pass through the feeder. The lower edge Mb of the fixedcam 10 on the other side of the stitch cam 6 is straight and horizontal.The parallel sides of the obliquely disposed recess are disposed at thesame angle as the operative edge 7 of the stitch cam, as a consequenceof which whenever the latter is adjusted up or down the said operativeedge will move in the same oblique line so that its relationship withthe aforementioned latch turn-over location will remain constant. Thiswill be evident from the fact that in Figure 2 the descending straightportions of the two waves W and W are coincident.

The inclined stitch cam 6, and also a guard cam 11 arranged beneath it,are fixed upon a common slide 12 a portion of which is slidable in acorrespondingly inclined slot 13 formed in the wall of the cam box'CB.The slide 12 is biassed upwardly bymeans of a compression spring 14 (seeFigure 3). The outer side of the cam slide 12 exposed at the exterior ofthe cylinder cam box CB is formed with a protuberant step-like lug 15upon the upper side of which is arranged to act the outer end of one arm16a of a lever 16. This lever is fulcrumed at 17 on the outside of thecam box and has an upstanding arm 16b arranged to be acted upon by anautomati-.

cally operable control member 18 which may, as shown in Figures 3 and 4,be actuated at appropriate times by or from a peg drum or like controlunit such as 19 mounted, in the case of a machine of the cylinder anddial type, on the top of the dial cam plate 20. the combined stitch andguard cams 6 and 11 can be automatically adjusted from time to timeaccording to knitting requirements. For the purpose of initially settingthe stitch cam 6 to draw loops of a pre-determined normal length, thereis provided, in this example, on the outside of the cam box CB, anadjusting screw 21 which has a knurled head 22 and is arranged with itsleading end pressing down on thetop of the lug 15 formed on the slide12.

As previously mentioned, a stitch cam adjustable in accordance with thisinvention may be made doubleended and reversible to enable it to presenta selected one of two circumferentially separated knocking'over points.Two such obliquely adjustable cams, incorporated in one cylinder cam boxsection, are shown at 23 in each of Figures 5 and 6. Each of these camswhich is attached, together with an associated guard cam 24, to a slide25, is differently contoured at its opposite ends so that by detachingit from its slide, turning it round end for end and then re-attaching itto the said slide, the knockingover point can be changed, according toknitting requirements. This will be clear from a comparison of Figures 5and 6. In Figure 5, the cams 23 are so arranged that their contouredends 23a oppose the guard cams 24 and the knocking-over points are at e,whereas in Figure 6 the same cams have been reversed so that theiropposite ends 23b now oppose the guard cams and the knockingover pointsare at 1, that is to say considerably to the left, and accordingly inadvance, of the points 2.

Double-ended and reversible stitch cams are accordingly useful whenaltering the set up of a machine to change from the production of, say,2 x 2 rib knitted fabric (Figure 5) to l x l rib fabric (Figure 6).Thus, for instance, in a cylinder and dial machine set up to produce 2 x2 fabric, the knocking-over point on the or each adjustable cylinderstitch cam must be in alignment with the knocking-over point on thecorresponding dial stitch cam so that both the dial and the cylinderneedles knockover together at the knitting location. For producing 1 x 1fabric, on the other hand, the knocking-over point on the cylinderstitch cam requires to be so disposed that the cylinder needlesknock-over earlier than the co-operating dial needles to acircumferential extent of as many as six or seven needles. This changecan readily be effected by the employment of a double-ended andreversible cylinder stitch cam at the or each feeder of the machine.

What I claim then is:

1. In a circular knitting machine, in combination, knit- In this way,

ting instruments provided with operating butts, and a cam systemincorporating a stitch cam having an inclined operative edge for actionon said butts, the said cam being adjustable obliquely at the same angleas its operative edge, being made double-ended and reversible suchwiseas to enable it, depending on its position, to present to the operatingbutts a selected one of two, circumferentially separated knocking-overpoints.

2. The knitting machine as defined in and claimed by claim 1 furthercharacterized in that a guard cam is combined with and adjustableconjointly and simultaneously with said stitch cam along the sameoblique line.

References Cited in the file of this patent UNITED STATES PATENTSVermilyea Sept. 9, 1884 Aiken Aug. 25, 1885 Klemm Oct. 15, 1907 IngallsJuly 27, 1915 Howie et a1. Aug. 1, 1922 Zieve et al July 5, 1949 Stibbeet al. Jan. 31, 1950

